Worst-case climate change scenario could be more extreme than thought, scientists warn

Economic growth could prompt greater greenhouse gas emissions than previously forecast, study says

Even our best efforts at limiting emissions may not be enough to avert disaster (Shutterstock)

Scientists may have to recalibrate their projections of what a “worst case” climate change scenario is, as new studies take into account greater global economic growth than previously forecast.

Climate scientists forecasting how the earth’s climate will change over time examine trends in greenhouse gas emissions, which are largely dependent on how the global economy behaves. As countries get richer, the amount they consume goes up, and so too do greenhouse gas emissions.

Scientists use four scenarios called representative concentration pathways (RCPs) that attempt to depict possible futures for our planet.

The standard worst case scenario, RCP 8.5, assumes rapid and unrestricted economic growth which will see rampant burning of fossil fuels. In addition, it also assumes no further action will be taken to limit warming than the policies countries are already pursuing.

However, scientists at the University of Illinois say there is a one-in-three chance that by the end of the century emissions will have exceeded those estimated in the RCP 8.5 scenario.

“Our estimates indicate that, due to higher than assumed economic growth rates, there is a greater than 35 per cent probability that year 2100 emissions concentrations will exceed those given by RCP8.5,” Peter Christensen told the New Scientist.

Glen Peters of the Centre for International Climate Research in Norway points to the rise in carbon emissions in Europe over the past four years as economic growth has sped up. In 2017, EU emissions rose by 1.8 per cent.

However, the worst case scenario remains unlikely as economic growth does not rule out environmentally-beneficial policy. “We’ve already locked in a certain amount of climate policy,” Mr Peters said.

Nonetheless, the latest research also means higher levels of emissions may now have to be factored in to the other climate scenarios.

Numerous climate models have previously predicted an apocalyptic future for existence on earth. From rapid icecap melt and catastrophic sea level rise, to rising temperatures making some areas uninhabitable, and mass extinctions of species in affected areas.

But even our best efforts may not be enough to avert disaster.

The Paris climate agreement commits the world’s countries to preventing global warming to no more than 2C above pre-industrial temperatures by the end of the century.

However, even if all countries meet their non-binding targets, some projections estimate global temperatures could still rise by more than 3C, and possibly by over 4C.

This would have a devastating effect on the planet, raising sea levels as much as 1.5 metres, putting cities like Amsterdam and New York under water and causing widespread famine.